I don't think you will find too much argument, its fairly accepted that glass bedding is the preferred way to bed a rifle. Its also accepted that aluminum bedding blocks are very good and suffice for most tactical rifles, but glass bedding is better for ultimate accuracy.
How about McMillan's claim that their A-4 and A-5 stocks don't need to be bedded at all? I've seen a couple of reviews which seemed to corroborate that point, do you think there was some bias in those writings?
As far as I know, McMillan says none of their stocks NEED to be bedded, but they recommend it. I purposely tested this with the SC1 prototype. Bedding my a very big difference. Its pretty widely accepted as a very good accuracy enhancing mod.